Dorcas R. Hardy came from California with the Reagan tide, believing in self-sufficiency and hoping to bring social service agencies into the computer age. Her mission: to remake the Office of Human Development Services, a grabbag of Health and Human Services programs for children, the elderly, native Americans and the mentally and physically disabled.

In the past two years, Hardy has come to appreciate the difficulty of putting a Republican soul in programs born and bred Democratic. As an assistant secretary at HHS and a front-line commander in the war on old Washington ways, she's had too much success to suit her critics and too little to suit herself.

"Budgetwise, we're the smallest thing on the block around here," said Hardy, a veteran of Ronald Reagan's state government. "But, fortunately or unfortunately, my constituents are the loudest."

Her aim is "to set down goals and objectives here in terms of pushing our population to be as self-sufficient as they can be. It's been assumed that you've got this population that needs all the help in the world and the only place help can come from is the federal government. I totally disagree with that."

Hardy has a crisp, businesslike manner, lacking the kind of fervor that arouses supporters and infuriates opponents. "If people in the department have problems we'll talk about it and settle them and go forward," she said. " . . . I do not consider myself autocratic. But I do have dictatorial tendencies. I know where I want to go."

Some initiatives suggest where that is:

* She wants to curb federal support for foster children. Under current law, a family supporting a foster child is supposed to be reimbursed. The administration's fiscal 1984 budget proposes to cap these funds. "I'm trying to get away from the notion that every time you see a foster child, you pay him," Hardy said.

* By contrast, she proposes no cap on adoption subsidy funds.

* She proposes to cut by nearly 50 percent state grants for such services as group homes, sheltered workshops and early screening of disabled children. Last year Congress rejected similar cuts. She also proposes to eliminate the $271 million work incentive program, which provides job training and counselling to welfare recipients.

* She allowed states to certify themselves for compliance with a 1980 law requiring states to monitor foster children and hold regular hearings on their placement. Critics concede that this process, followed by an HHS review of state decisions, may be preferable to a long rule-making process to develop guidelines for federal certification.

Hardy has evoked predictably mixed reactions among her office's complex and fractious network of constituents. Coalitions of state social service agencies are cautiously pleased with the new respect they get from her office, though they object to the budget cuts.

Advocacy groups, which distrust state agencies and fervently backed some laws that Hardy and the states find onerous, express dislike for her. Spokesmen for social service research groups, many of whom found their basic assumptions turned upside down with Hardy's arrival, use gentlemanly reserve in expressing their distaste.

Hardy's greatest success has been in centralizing most of her office's research funds and setting up a new layer of specialized panels to evaluate some 6,000 annual applications--a success which, as the newsletter Child Protection Report pointed out, has proved providential to her former employer, the Center for Health Sciences Research at the University of Southern California Medical School.

The USC center will get about $493,000 on three projects this year. That represents about a 50 percent increase in OHDS grants, which now make up one-third of the center's $1.3 million budget, according to Edward M. Young, its associate director.

"They . . . understand what we're trying to do," said Hardy. "There's some talent in all these research organizations. Whether I agree with them or not is irrelevant. I'm trying to drive an HDS agenda of social and economic development . . . . I don't think my limited resources should . . . train five more people to go and save the world."

The Child Welfare League of America, by contrast, lost a $1 million grant to set up a national adoption registry for hard-to-place children; the funds went to another group. The league has supported child welfare policies Hardy opposes.

Overall, the administration proposes to cut central research funds from $22.2 million to $9 million in fiscal 1984.

Other cuts proposed by Hardy have not fared well in Congress. In 1982, Hardy proposed $730 million in cuts, but since 1980, the office's budget has declined only $250 million. The only program the administration regards as sacrosanct is Head Start, the educational program for 400,000 poor preschoolers. If Congress approves, Head Start would get a $138 million budget increase next year.

In Hardy's first budget fight in 1981, she backed the administration's proposed social services block grant, only to see it whittled down to five programs. Opposition emerged from an unexpected quarter when former representative John Rousselot (R-Calif.), a longtime Reagan supporter, fought hard to keep foster care programs out of the block grant.

In 1982, her proposed child welfare services block grant quickly died. She tried to resurrect it this year, but was rebuffed by HHS officials reluctant to pursue what they thought was a lost cause.

"I'm not disappointed because I know things take longer than you want them to," Hardy said. "You learn that real quickly . . . . But I'm not going to change horses in midstream."